/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/

/*
 *  Public Key abstraction layer
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */

#include "tls/config.h"

#if defined(MBEDTLS_PK_C)
#include "tls/pk.h"
#include "tls/pk_internal.h"

#if defined(MBEDTLS_RSA_C)
#include "tls/rsa.h"
#endif
#if defined(MBEDTLS_ECP_C)
#include "tls/ecp.h"
#endif
#if defined(MBEDTLS_ECDSA_C)
#include "tls/ecdsa.h"
#endif

/* Implementation that should never be optimized out by the compiler */
static void mbedtls_zeroize(void *v, size_t n)
{
	volatile unsigned char *p = v;
	while (n--) {
		*p++ = 0;
	}
}

/*
 * Initialise a mbedtls_pk_context
 */
void mbedtls_pk_init(mbedtls_pk_context *ctx)
{
	if (ctx == NULL) {
		return;
	}

	ctx->pk_info = NULL;
	ctx->pk_ctx = NULL;
}

/*
 * Free (the components of) a mbedtls_pk_context
 */
void mbedtls_pk_free(mbedtls_pk_context *ctx)
{
	if (ctx == NULL || ctx->pk_info == NULL) {
		return;
	}

	ctx->pk_info->ctx_free_func(ctx->pk_ctx);

	mbedtls_zeroize(ctx, sizeof(mbedtls_pk_context));
}

/*
 * Get pk_info structure from type
 */
const mbedtls_pk_info_t *mbedtls_pk_info_from_type(mbedtls_pk_type_t pk_type)
{
	switch (pk_type) {
#if defined(MBEDTLS_RSA_C)
	case MBEDTLS_PK_RSA:
		return (&mbedtls_rsa_info);
#endif
#if defined(MBEDTLS_ECP_C)
	case MBEDTLS_PK_ECKEY:
		return (&mbedtls_eckey_info);
	case MBEDTLS_PK_ECKEY_DH:
		return (&mbedtls_eckeydh_info);
#endif
#if defined(MBEDTLS_ECDSA_C)
	case MBEDTLS_PK_ECDSA:
		return (&mbedtls_ecdsa_info);
#endif
		/* MBEDTLS_PK_RSA_ALT omitted on purpose */
	default:
		return (NULL);
	}
}

/*
 * Initialise context
 */
int mbedtls_pk_setup(mbedtls_pk_context *ctx, const mbedtls_pk_info_t *info)
{
	if (ctx == NULL || info == NULL || ctx->pk_info != NULL) {
		return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
	}

	if ((ctx->pk_ctx = info->ctx_alloc_func()) == NULL) {
		return (MBEDTLS_ERR_PK_ALLOC_FAILED);
	}

	ctx->pk_info = info;

	return (0);
}

#if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
/*
 * Initialize an RSA-alt context
 */
int mbedtls_pk_setup_rsa_alt(mbedtls_pk_context *ctx, void *key, mbedtls_pk_rsa_alt_decrypt_func decrypt_func, mbedtls_pk_rsa_alt_sign_func sign_func, mbedtls_pk_rsa_alt_key_len_func key_len_func)
{
	mbedtls_rsa_alt_context *rsa_alt;
	const mbedtls_pk_info_t *info = &mbedtls_rsa_alt_info;

	if (ctx == NULL || ctx->pk_info != NULL) {
		return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
	}

	if ((ctx->pk_ctx = info->ctx_alloc_func()) == NULL) {
		return (MBEDTLS_ERR_PK_ALLOC_FAILED);
	}

	ctx->pk_info = info;

	rsa_alt = (mbedtls_rsa_alt_context *) ctx->pk_ctx;

	rsa_alt->key = key;
	rsa_alt->decrypt_func = decrypt_func;
	rsa_alt->sign_func = sign_func;
	rsa_alt->key_len_func = key_len_func;

	return (0);
}
#endif							/* MBEDTLS_PK_RSA_ALT_SUPPORT */

/*
 * Tell if a PK can do the operations of the given type
 */
int mbedtls_pk_can_do(const mbedtls_pk_context *ctx, mbedtls_pk_type_t type)
{
	/* null or NONE context can't do anything */
	if (ctx == NULL || ctx->pk_info == NULL) {
		return (0);
	}

	return (ctx->pk_info->can_do(type));
}

/*
 * Helper for mbedtls_pk_sign and mbedtls_pk_verify
 */
static inline int pk_hashlen_helper(mbedtls_md_type_t md_alg, size_t *hash_len)
{
	const mbedtls_md_info_t *md_info;

	if (*hash_len != 0) {
		return (0);
	}

	if ((md_info = mbedtls_md_info_from_type(md_alg)) == NULL) {
		return (-1);
	}

	*hash_len = mbedtls_md_get_size(md_info);
	return (0);
}

/*
 * Verify a signature
 */
int mbedtls_pk_verify(mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hash_len, const unsigned char *sig, size_t sig_len)
{
	if (ctx == NULL || ctx->pk_info == NULL || pk_hashlen_helper(md_alg, &hash_len) != 0) {
		return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
	}

	if (ctx->pk_info->verify_func == NULL) {
		return (MBEDTLS_ERR_PK_TYPE_MISMATCH);
	}

	return (ctx->pk_info->verify_func(ctx->pk_ctx, md_alg, hash, hash_len, sig, sig_len));
}

/*
 * Verify a signature with options
 */
int mbedtls_pk_verify_ext(mbedtls_pk_type_t type, const void *options, mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hash_len, const unsigned char *sig, size_t sig_len)
{
	if (ctx == NULL || ctx->pk_info == NULL) {
		return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
	}

	if (!mbedtls_pk_can_do(ctx, type)) {
		return (MBEDTLS_ERR_PK_TYPE_MISMATCH);
	}

	if (type == MBEDTLS_PK_RSASSA_PSS) {
#if defined(MBEDTLS_RSA_C) && defined(MBEDTLS_PKCS1_V21)
		int ret;
		const mbedtls_pk_rsassa_pss_options *pss_opts;

		if (options == NULL) {
			return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
		}

		pss_opts = (const mbedtls_pk_rsassa_pss_options *)options;

		if (sig_len < mbedtls_pk_get_len(ctx)) {
			return (MBEDTLS_ERR_RSA_VERIFY_FAILED);
		}

		ret = mbedtls_rsa_rsassa_pss_verify_ext(mbedtls_pk_rsa(*ctx), NULL, NULL, MBEDTLS_RSA_PUBLIC, md_alg, (unsigned int)hash_len, hash, pss_opts->mgf1_hash_id, pss_opts->expected_salt_len, sig);
		if (ret != 0) {
			return (ret);
		}

		if (sig_len > mbedtls_pk_get_len(ctx)) {
			return (MBEDTLS_ERR_PK_SIG_LEN_MISMATCH);
		}

		return (0);
#else
		return (MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE);
#endif
	}

	/* General case: no options */
	if (options != NULL) {
		return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
	}

	return (mbedtls_pk_verify(ctx, md_alg, hash, hash_len, sig, sig_len));
}

/*
 * Make a signature
 */
int mbedtls_pk_sign(mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hash_len, unsigned char *sig, size_t *sig_len, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
	if (ctx == NULL || ctx->pk_info == NULL || pk_hashlen_helper(md_alg, &hash_len) != 0) {
		return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
	}

	if (ctx->pk_info->sign_func == NULL) {
		return (MBEDTLS_ERR_PK_TYPE_MISMATCH);
	}

	return (ctx->pk_info->sign_func(ctx->pk_ctx, md_alg, hash, hash_len, sig, sig_len, f_rng, p_rng));
}

/*
 * Decrypt message
 */
int mbedtls_pk_decrypt(mbedtls_pk_context *ctx, const unsigned char *input, size_t ilen, unsigned char *output, size_t *olen, size_t osize, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
	if (ctx == NULL || ctx->pk_info == NULL) {
		return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
	}

	if (ctx->pk_info->decrypt_func == NULL) {
		return (MBEDTLS_ERR_PK_TYPE_MISMATCH);
	}

	return (ctx->pk_info->decrypt_func(ctx->pk_ctx, input, ilen, output, olen, osize, f_rng, p_rng));
}

/*
 * Encrypt message
 */
int mbedtls_pk_encrypt(mbedtls_pk_context *ctx, const unsigned char *input, size_t ilen, unsigned char *output, size_t *olen, size_t osize, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
	if (ctx == NULL || ctx->pk_info == NULL) {
		return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
	}

	if (ctx->pk_info->encrypt_func == NULL) {
		return (MBEDTLS_ERR_PK_TYPE_MISMATCH);
	}

	return (ctx->pk_info->encrypt_func(ctx->pk_ctx, input, ilen, output, olen, osize, f_rng, p_rng));
}

/*
 * Check public-private key pair
 */
int mbedtls_pk_check_pair(const mbedtls_pk_context *pub, const mbedtls_pk_context *prv)
{
	if (pub == NULL || pub->pk_info == NULL || prv == NULL || prv->pk_info == NULL || prv->pk_info->check_pair_func == NULL) {
		return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
	}

	if (prv->pk_info->type == MBEDTLS_PK_RSA_ALT) {
		if (pub->pk_info->type != MBEDTLS_PK_RSA) {
			return (MBEDTLS_ERR_PK_TYPE_MISMATCH);
		}
	} else {
		if (pub->pk_info != prv->pk_info) {
			return (MBEDTLS_ERR_PK_TYPE_MISMATCH);
		}
	}

	return (prv->pk_info->check_pair_func(pub->pk_ctx, prv->pk_ctx));
}

/*
 * Get key size in bits
 */
size_t mbedtls_pk_get_bitlen(const mbedtls_pk_context *ctx)
{
	if (ctx == NULL || ctx->pk_info == NULL) {
		return (0);
	}

	return (ctx->pk_info->get_bitlen(ctx->pk_ctx));
}

/*
 * Export debug information
 */
int mbedtls_pk_debug(const mbedtls_pk_context *ctx, mbedtls_pk_debug_item *items)
{
	if (ctx == NULL || ctx->pk_info == NULL) {
		return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
	}

	if (ctx->pk_info->debug_func == NULL) {
		return (MBEDTLS_ERR_PK_TYPE_MISMATCH);
	}

	ctx->pk_info->debug_func(ctx->pk_ctx, items);
	return (0);
}

/*
 * Access the PK type name
 */
const char *mbedtls_pk_get_name(const mbedtls_pk_context *ctx)
{
	if (ctx == NULL || ctx->pk_info == NULL) {
		return ("invalid PK");
	}

	return (ctx->pk_info->name);
}

/*
 * Access the PK type
 */
mbedtls_pk_type_t mbedtls_pk_get_type(const mbedtls_pk_context *ctx)
{
	if (ctx == NULL || ctx->pk_info == NULL) {
		return (MBEDTLS_PK_NONE);
	}

	return (ctx->pk_info->type);
}

#endif							/* MBEDTLS_PK_C */
